The present disclosure relates to semiconductor memory devices and, more particularly, to nonvolatile memory devices and/or erasing methods thereof.
Semiconductor memory device are memory devices implemented using a semiconductor such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), and indium phosphide (InP). In general, semiconductor memory devices may be classified as volatile memory devices and nonvolatile memory devices.
Volatile memory devices lose their stored data when their power supplies are interrupted. Volatile memory devices may include a static RAM (SRAM), a dynamic RAM (DRAM), and a synchronous DRAM (SDRAM). Nonvolatile memory devices are memory devices that retain their stored data even when their power supplies are interrupted. Nonvolatile memory devices may include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory device, a phase change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), and a ferroelectric RAM (FRAM). Flash memory devices are classified as NOR-type flash memory devices and NAND-type flash memory devices.
In recent years, semiconductor memory devices having a three-dimensional array structure have been researched to improve the integration density of semiconductor memory devices. A semiconductor memory device having a three-dimensional structure is tending to increase in stacked height. The more the stacked height increases, the greater the number of memory cells may be included in a single memory block. Accordingly, in the case of a semiconductor memory device that performs an erase operation in units of memory blocks, the number of memory cells included in an erase unit may increase. Thus, the number of memory blocks in the semiconductor may decrease. If the number of the memory blocks decreases, there may be a limitation in the number of blocks that can be replaced when a failure or a progressive failure caused by a process occurs. As a result, productivity of the semiconductor memory device may be reduced.